6 
decimals, for four emplacements this battery would require in ordinary soil 100 
men working eight hours. 
Fig. 2a. 
The magazines should be in excavations outside the batteries, niches for the re- 
ception of a few rounds being excavated near each gun. 
Local circumstances may prevent such batteries being constructed. 
(1.) The configuration of the ground may necessitate more command than can 
be obtained from a sunken battery. 
(2.) Water near the surface or a very soft subsoil would oblige the guns to be 
placed on unbroken ground. 
(8.) A very rocky ground might render excavation too laborious, in this case 
the conformation of the ground might admit of the guns being placed as shewn 
in fig. 2a. 
Whenever a sunken battery is excavated in rock the danger of splinters from 
the rear face of the emplacement must be guarded against, the slope of this face 
should not be too steep and, if necessary, the length along the line of fire of the 
emplacement should be increased, the extra space being filled up with earth at a 
slope of ¢ or 4 from the ground level to the floor of the emplacement. When- 
ever it is necessary to protect batteries by raised parapets owing to the nature of 
the soil, difficulties of drainage, &c., it will be impossible to conceal them from 
view, but observation of fire by the enemy must be rendered difficult by the em- 
ployment of natural or artificial screens or masks. Lofty trees form the best 
screen, especially if planted in suitable rows, the distance of such a screen from 
the battery must depend on the height of the trees, local considerations, &c., but 
it should be at some considerable distance (100 to 300 yards). 
In default of natural. screens recourse must be had to masses of earth, here 
again no exact distance can be laid down, but in any case it should not be less 
than the length of the 50°/, zone for the guns likely to be employed against it at 
the shortest probable range. 
When the position of the batteries is commanded in such a way that it is not 
possible to screen them, the position of the guns may be concealed by a cloud of 
smoke from fires lighted in suitable positions and fed with resinous, smoke- 
giving fuel. 
Concealed batteries (8rd ¢chelon). These batteries being constructed on the re- 
verse slope will only require overhead cover and the magazines can be placed close 
to the batteries. The arrangement of such batteries being reduced to the utmost 
simplicity will facilitate the rapid instalment of such ordnance as may at any time 
be required at any particular spot, whether for offence or defence. When the 
features of the ground are not acutely marked the positions of the batteries must 
be masked by screens as recommended above; finally, if it is impossible to utilize 
any of the above methods to protect and screen the batteries, recourse must be had 
to armoured protection. 
The advantage of armour for the protection of important guns mounted in the 
permanent forts is undisputed, but its employment for the protection of batteries 
placed in the intervals presents many difficulties. Shields for the protection of 
siege batteries formed of layers of plates of the aggregate thickness of 5°85" have 
been tried, and it is not impossible that the employment of more powerful shields 
